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Host And Defense Exam 4 > German - Immune System Failure > Flashcards

German - Immune System Failure Flashcards

1
Q

How do pathogens evade the immune system? 5

A

Serotype diversity

Antigenic drift

Antigenic shift

Gene conversion

Latency

Avoid the immune system

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2
Q

How do pathogens subvert the immune system? 6

A

Endocytic hijacking

Protein mimicry

Humoral inhibition

Inflammation inhibition

Immunosuppression

Superantigens

*COMMANDEER the immune system

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3
Q

What is serotype diversity?

A

Antigenically different strains of the same pathogen

  • High genetic variability
  • Not necessarily highly mutable
  • Useful for tracking outbreaks
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4
Q

What is an example of serotype diversity?

A

One serotype of S. Pneumoniae infects
-Antibody response clears the infection

Another serotype infects
-Body has to now clear a second infection

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5
Q

What is antigenic drift?

A

Mutation in the viral genome driven by selective pressure as the virus infects a population

  • Viral genomes are highly mutable
  • Tied to memory erosion
  • Responsible for viral epidemics
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6
Q

Example of antigenic drift?

A

Influenza spreading thru a GEOGRAPHICAL population
-Antibody binding to hemagglutinin prevents virus V form infecting a person
—It can mutate and now the body can’t prevent infection

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7
Q

What is antigenic shift?

A

Genetic recombination that leads to significant change in viral antigens
-Responsible for viral PANDEMICS
—Two separate viruses that fuse together
—Chicken infected with chicken flu and human flu will have the two viral genomes recombining which results in a new, potent virus

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8
Q

What is gene conversion?

A

Trypanosomes change cell surface glycoprotein expression

So, they just “shift” to the next VSG

VSG gene rearrangement

  • One VSG is dominant at any time
  • Minority express other VSGs

Humoral evasion

Population cycling with VSG expression

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9
Q

Epidemic is within _________

Pandemic is _________

A

A nation/area

Global

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10
Q

What is VSG?

A

Variable surface glycoprotein

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11
Q

What is latency?

A

Viral dormant state in host tissue

  • Immune privileged tissue
  • Reduced viral load
  • Absent or reduced IFN response and MHC I expression
  • NK and CD8 T cell evasion
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12
Q

Examples of latency?

A 
HSV
CMV
VZV
EBV
Parvoviruses
Adenoviruses
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13
Q

What cause recurrent emergence?

A

Stress

Concurrent infection

Compromised immunity

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14
Q

What is endocytic hijacking?

A

Utilize endocytosis for cellular entry

Prevent lysosome fusion

Escape phagosomes

Survive autolysosomal environment

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15
Q

What is antigen mimicry?

A

Adult worms coat themselves in host protein

Surface antigens are regularly shed

Antibody evasion and removal

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16
Q

What are superantigens?

A

Potent toxins that disrupt immune fx

G+ bacteria

  • Staph A
  • Strep pyogenes

Non-specific T cell activation

  • Randomly activated
  • Adaptive immune system “ramps” up for nothing

Ab and complement INACTIVATION

17
Q

What is primary immunodeficiency?

A

Genetically caused immune system deficiency

18
Q

What are the 3 types of primary immunodeficiency?

A

Dominant

Recessive

X-linked

19
Q

What is secondary immunodeficiency?

A 
Immune deficiency caused by environmental factors
-Chronic disease
-Immunosuppressive drugs
-Viral
—HIV
-Environmental toxins
20
Q

What are 4 viral strategies for subversion?

A

Inhibition of humoral immunity

  • Virally encoded Fc receptor
  • HSV, CMV, Vaccinia

Inhibition of inflammatory response

  • Virally encoded chemokine receptor homolog
  • CMV, Vaccinia, EBV

Blocking of antigen processing and presentation

  • Inhibition of MHC I upregged by IFN-gamma
  • HSV, CMV

Immunosuppression of host

  • Virally encoded cytokine homolog of IL-10
  • EBV
21
Q

In primary immunodeficiency, there are dominant and recessive alleles.

Tell me about recessive immunodeficiencies.

Tell me about dominant immunodeficiencies.

A

Recessive - 2 recessive alleles for deficiency

Dominant - 1 dominant allele for deficiency

22
Q

What kinase is associated with X-linked disorders?

A

Bruton’s tyrosine kinase (BTK)

23
Q

Tell me what BTK is necessary for?

A

B cell signaling

24
Q

BTK is on the ____ chromosome.

BTK males and homozygous females do not develop ____ ________.

BTK heterozygous females are ___________.

A

X

B cells

Carriers

25
Q

What are the 5 classes of primary immunodeficiency?

A

Humoral immunity

Cellular immunity

Combined

Phagocytic cells

Complement

26
Q

What does a kinase do?

A

Phosphorylates

27
Q

Tell me about humoral immunity.

A
  • 60%
  • Reduced or absent serum immunoglobulin
  • Impaired B cells
  • Selective IgA deficiency is the most common
28
Q

Tell me about cellular immunity.

A

-10%
-Impaired T cells
-Predisposition to viral, fungal, and opportunistic pathogens
-Most common
—DiGeorge Syndrome
—ZAP-70 deficiency
-X-linked lymphoproliferative syndrome
-Chronic mucocutaneous candidiasis

29
Q

Tell me about combined primary immunodeficiency.

A
  • 20%
  • Deficiencies in both B and T cell fx
  • Severe combined immunodeficiencies
30
Q

Tell me about phagocytic cells in primary immunodeficiency.

A

-10%
-Impaired phagocytosis
-Frequent G- infections
-Most common
—Chronic granulomatous disease
—Leukocyte adhesion deficiency
—Chediak-Higashi syndrome

31
Q

Tell me about complement in terms of primary immunodeficiency.

A
  • Very rare (<2%)
  • Deficiencies in complement components, inhibitors, or their production
  • Recurrent bacterial infection
  • Autoimmune disorders
32
Q

HIV leads to ________.

A

AIDS

33
Q

Tell me about HIV/AIDS.

A

Secondary immunodeficiency

Highly mutable
-Change rapidly and regularly

Blood and sexual fluid transmission

Targets CD4 T cells
-These are most common in the blood
-These are needed to mobilize adaptive immunity
—Antibody production is greatly affected

*Once the body does develop a response to the virus, the HIV then changes serotype and develops a “new” virus
—This leads to death

34
Q

T/F -HIV is a retrovirus.

A

TRUE

Host And Defense Exam 4 (10 decks)

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